Brain fog is a common lupus symptom and a possible side effect of lupus treatments. Some members of MyLupusTeam have wondered if brain fog is a side effect of hydroxychloroquine (Plaquenil). This is a medication used to treat lupus — the most common type of which is systemic lupus erythematosus (SLE). Brain fog is not commonly associated with hydroxychloroquine (HCQ), but rather, it is a symptom frequently experienced by individuals living with lupus. Therefore, if you have lupus, you may have episodes of brain fog from time to time.

After beginning HCQ, one MyLupusTeam member wrote, “When I started the morning dose, I noticed I felt out of it, kind of like I took a muscle relaxant. Then, by 2 o’clock at work, I had a hard time doing anything, couldn’t think straight, and felt like I needed to go to bed.”

Another member wrote, “I believe taking Plaquenil was when my brain fog started. I was sure that I had developed attention deficit disorder. I couldn’t think straight. I couldn’t remember things. I felt dumb, honestly.”

What Is Brain Fog?

Brain fog describes general cognitive impairment — such as forgetting things or struggling to concentrate. Although everyone experiences brain fog differently, common symptoms include:

• Having trouble remembering facts or memories
• Taking longer than usual to perform tasks or solve problems
• Struggling to hold conversations
• Experiencing difficulty with focus or concentration

Anyone can experience brain fog, and everyday experiences such as lack of sleep or pain may trigger an episode. Thankfully, there are strategies for coping with brain fog, including the following:

• Avoid triggers prone to causing flare-ups.
• Use memory aids, such as lists or writing things down.
• Get enough sleep and exercise.

Does Hydroxychloroquine Cause Brain Fog?

HCQ works to block certain proteins in the immune system that are responsible for inflammation. For this reason, it’s often effective at preventing inflammation and long-term organ damage in lupus.

Although brain fog is not a reported side effect of HCQ, you’re not imagining your symptoms. Because brain fog commonly occurs with lupus, the coordinated timing of brain fog and starting HCQ is likely a coincidence.

Alternatively, starting HCQ means that you might experience other medication side effects that can make brain fog worse, such as nervousness or fatigue. Finally, other lupus medications are associated with brain fog or cognitive dysfunction.

Lupus Can Cause Brain Fog

Brain fog is especially common in people living with lupus. According to one estimate from the Lupus Foundation of America, 70 percent to 80 percent of people diagnosed with lupus experience brain fog during their lives.

Why is brain fog so common in individuals living with lupus? Lupus, like rheumatoid arthritis and multiple sclerosis, is an autoimmune disease — a condition in which your immune cells attack your own body, causing damage and inflammation. When inflammation occurs in your skin, it often results in rashes, sores, or lesions. However, when your nervous system is inflamed, brain fog and other symptoms such as seizures or dizziness can occur. In fact, inflammation of the nervous system is the leading cause of brain fog, which explains why people living with lupus would be at a greater risk for developing the condition.

One difficult aspect of lupus is that its symptoms are intermittent — in other words, you may go through flare-ups (periods of time when symptoms get worse) and remissions (periods of time when symptoms are rare). As a result, predicting when brain fog will occur is difficult. Moreover, if this symptom happens to coincide with when you begin a new activity, such as starting a sport or taking a new medication, you may be unsure if the flare-up or new activity is responsible for it. In these cases, you can always seek medical advice from your doctor if you have any concerns about potential adverse effects from your new activities or treatments.

Other Hydroxychloroquine Side Effects May Trigger Brain Fog

Because HCQ reduces inflammation, shouldn’t starting HCQ prevent brain fog? HCQ is fairly slow-acting, so you may need to wait one to three months to see any improvements in your lupus symptoms. Some people don’t feel the full benefit of HCQ until a year after starting on it.

Furthermore, you may feel worse from taking HCQ before you begin to feel better. Although HCQ is considered a safe medication, it can still cause side effects. In addition, HCQ has known drug interactions with antibiotics and diabetes medications, which are adverse reactions that occur when mixing two medications.

Although many people will not have any side effects at all, others may experience the following issues when first starting HCQ:

• Nausea and vomiting
• Other digestive issues, such as loss of appetite, cramps, and diarrhea
• Tiredness or weakness
• Headache

In rare cases, HCQ may also cause eye damage. Taking a high dose of HCQ or other common antimalarials, such as chloroquine, is a common risk factor for retinal damage.

Although brain fog is not a reported side effect of HCQ, a lack of sleep or other triggers caused by these symptoms can make brain fog worse, especially because HCQ’s beneficial effects may not be felt right away. Headaches and dizziness, which can occur while on HCQ, are also associated with brain fog.

Generally, any adverse effects, besides eye damage, are short term and should go away on their own while you’re taking the drug.

Other Lupus Treatments Can Cause Brain Fog

Besides HCQ, other lupus medications your rheumatologist might prescribe include steroids, nonsteroidal anti-inflammatories (NSAIDs), and immunosuppressives like methotrexate (Rheumatrex). Prednisone, a common steroid used to treat lupus, can cause changes in cognition, like brain fog. Specifically, you can experience confusion, nervousness, or hallucinations.

One MyLupusTeam member wrote about how their loved one experienced brain fog while on prednisone. They mentioned, “My oldest daughter used to tell me while taking prednisone that she felt like she was trying to think through mud.”

Because brain fog often leaves no physical mark and comes and goes in waves, you may sometimes wonder if you imagined what happened. Although brain fog isn’t a common side effect of HCQ, your symptoms are real. Your lupus, other side effects of HCQ, or a different medication may cause your brain fog.

Talk With Others Who Understand

MyLupusTeam is the social network for people with lupus and their loved ones. On MyLupusTeam, more than 223,000 members come together to ask questions, give advice, and share their stories with others who understand life with lupus.

Have you experienced brain fog while taking hydroxychloroquine for lupus? How did you manage it? Share your experience in the comments below, or start a conversation by posting on your Activities page.